Collaboration Agreements - Additional Information (Details) $ in Thousands			1 Months Ended							3 Months Ended
	Aug. 17, 2021 USD ($)	Jul. 01, 2021 USD ($)	Dec. 31, 2023 USD ($)	May 31, 2023 USD ($)	Mar. 31, 2023 USD ($)	Feb. 28, 2023 USD ($)	Jan. 31, 2022 USD ($)	Jan. 31, 2018 USD ($)	Oct. 31, 2017 USD ($)	Mar. 31, 2024 USD ($)	Sep. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development expense										$ 45,167		$ 51,887
GlaxoSmithKline plc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Effective date of agreement	Aug. 17, 2021
Upfront payments		$ 700,000								$ 700,000
Milestone payment received	$ 500,000						$ 200,000
Additional milestone payments to support the enrollment	$ 500,000						$ 200,000
Percentage of development cost										0.60
Collaboration revenue										$ 8,700		11,400
Deferred revenue			$ 247,400							238,700
Research and development expense										4,600		2,100
Reduction in transaction price											$ 4,200
Transaction price										569,000
Contract with customer, refund liability				$ 128,400
Maximum funding				140,500
Cumulative adjustment to revenue				26,900							$ 4,900
GlaxoSmithKline plc | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Additional milestone payments related to initiation of certain clinical studies and regulatory approval										1,500,000
Transaction price		$ 700,000
GlaxoSmithKline plc | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Transaction price				$ 571,600
GlaxoSmithKline plc | Change in Estimate [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract with customer, refund liability										$ 94,800
Alector
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of development cost										0.40
AbbVie Biotechnology Limited
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payments									$ 205,000	$ 205,000
Milestone payment received			12,500		$ 17,800			$ 200,000	5,000	17,800
Exclusive option rights exercised for each program									250,000
Additional milestone payments to support the enrollment			12,500		$ 17,800			$ 200,000	5,000	17,800
Collaboration revenue										7,200		5,200
Deferred revenue			$ 46,400							39,300
Payment for enrollment of additional patients										$ 12,500
AbbVie Biotechnology Limited | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payment received						$ 12,500
Additional milestone payments related to initiation of certain clinical studies and regulatory approval									$ 225,000
Additional milestone payments to support the enrollment						$ 12,500
AbbVie Biotechnology Limited | Deferred Revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration revenue												$ 2,000